It is actually working as intended. Many laptops only allow the battery to be charged up to a certain before the charging stops unless you override it.
The reason is due to a chemical reaction where if the battery is holding a charge close to it's maximum capacity for a long time the lithium ions start combining together to form "lithium plates". When this happens the battery capacity begins to fall; so in other words, the longer the battery is near it's maximum capacity, the faster it will fail.
As long as you are connected the laptop to the AC outlet, just let it charge up to 60%. When you know you are going to need to use it away from the home / office, then charge up to 100%.